Two of their children had cancer. Ted Jr. developed bone cancer at age 12, which resulted in the removal of a portion of his right leg in 1973, and Kara was treated for lung cancer in 2003.[4] Kara Kennedy died of a heart attack at age 51 on September 16, 2011.

Ted suffered a severe back injury in a 1964 airplane crash while campaigning for his first full term in the U.S. Senate. She assumed the full campaign-appearance schedule for his successful re-election in 1964. He had earlier won a special election in November 1962 to serve the final two years of his brother John's U.S. Senate term; John had resigned from the U.S. Senate upon his 1960 election as U.S. President.

In July 1969, Ted Kennedy was involved in a car accident off Chappaquiddick Island in Massachusetts that resulted in the drowning death of his passenger, Mary Jo Kopechne.[5] Although pregnant and confined to bed in the wake of two previous miscarriages, she attended Kopechne's funeral. Three days later she stood beside her husband in court when he pleaded guilty to leaving the scene of an accident. She suffered a third miscarriage shortly thereafter.[6]

Joan Kennedy in Boston at the Rose Parade celebration of Rose Kennedy's 90th birthday in 1980

In 1992, she published the book The Joy of Classical Music: A Guide for You and Your Family. Her later years have been shaped by chronic alcoholism, which had appeared during her marriage. It escalated with sporadic, uneven sobriety, repeated drunk-driving arrests,[2] court-ordered rehabilitation,[2] and a return to drinking. This ultimately led to kidney damage, with the possibility of dialysis[3] and protracted complications. Kennedy has worked with children's charities, remains an accomplished pianist and has taught children classical music.[10]

In July 2004, her son Ted Jr. had been appointed her legal guardian; in 2005 her children were granted temporary guardianship. That year, she was hospitalized with a concussion and a broken shoulder after being found lying in a Boston street near her home.[2][11][12] At her request in 2005, her second cousin, financial planner Webster E. Janssen of Connecticut, established a trust controlling her estate in violation of her sons' guardianship. Her children later took successful legal action against Janssen, removing him as trustee and later filing a complaint against him with the U.S. Securities and Exchange Commission.[13] That October, She was diagnosed with breast cancer and underwent surgery.[14] She agreed to strict court-ordered guardianship and her estate has since been placed in a new trust overseen by two court-appointed trustees.[3]

Apart from a brief relationship shortly after her divorce, she has neither remarried nor pursued another relationship.[3] She attended Ted's funeral at the Kennedy compound in Hyannis Port.[15] As of 2005, she resides in Boston, Massachusetts and Cape Cod.[2]